Is it global warming or something else?
A recently published animation of the giant iceberg that was ‘created’ off the Pine Island Glacier in West Antarctica just over two months ago shows an unexpected disintegration, and scientists say it’s worrying.
Satellite images revealed the formation of a 160-square kilometer iceberg from the ice front of the Pine Island Glacier in Antarctica in September.
The event was not a complete surprise, but it is a worrying signal for the future rise in sea level.
Pine Island is the largest contributor in Antarctica to this phenomenon.
The scientists hoped that the iceberg will penetrate into the Southern Ocean before breaking. However, it got stuck, probably prevented by thick sea ice, before it began to disintegrate into many smaller icebergs.
Robert Larter, a marine geophysicist with the British Antarctic Survey, who overflew the fault on Pine Island last season during his research cruise with the German Institute Alfred Wegener, said in a statement:
“What we’re seeing on Pine Island Glacier is extremely worrying noted the expert.”
“We’re now observing changes in the calving behavior of the ice shelf when for 68 years we saw a pattern of advance and retreat resulting in the calving of a single large iceberg which left the ice front to approximately the same place. The calving of icebergs in 2001, 2007 and 2013 are well-documented. Each calving event returned the ice front to more or less the same position, and the ice shelf flowed into the sea again. But with continuing thinning it was clear that sooner or later there would have to be a change to this pattern – and this is what we are witnessing now.”
Jeong et al https://t.co/AvjnfahbGx give an overview of the previous events, the exceptional internal rifts and calving front migration 5/n pic.twitter.com/rjLLDVtKFl
— Stef Lhermitte (@StefLhermitte) September 23, 2017
“What’s both interesting and of concern is the lines along which the iceberg has broken follow the pattern of crevasses developed in the ice shelf that it calved from. This change of behavior might reflect the crevasses within the ice shelf having an increasing influence on the spacing and pattern of iceberg calving as a result of the thinning that has taken place over the past few decades.”
Pine Island is the fastest melting glacier in Antarctica, one that is responsible for a quarter of the loss of ice from the frozen continent, about 45 billion tons of ice per year. Satellite images taken since September 26 show an open water gap that arises between the ice shelf and the iceberg.
This event is of great importance because, despite the fact that the ice shelf has been declining for decades, until two years ago there had been no systematic retreat of the ice front as it was first witnessed in 1947.
Dr. Larter concluded: “If the ice shelf continues to thin and the ice front continues to retreat, its buttressing effect on PIG will diminish, which is likely to lead to further dynamic thinning and retreat of the glacier. PIG already makes the largest contribution to sea-level rise of any single Antarctic glacier and the fact that its bed increases in depth upstream for more than 200 km means there is the possibility of runway retreat that would result in an even bigger contribution to sea level.”